1. Today: Meiosis, producing genetically diverse offspring, and inheritance

2. For life to exist, the information (genes) must be passed on.
{Meiosis:
producing gametes}
For life to exist, the information (genes) must be passed on.
{Mitosis:
producing more cells}

3. Voles Prairie Monogamous Both parents care for young Montane
Nonmonogamous
Mother cares for young briefly

4. Voles Prairie Monogamous Both parents care for young More receptors
Montane
Nonmonogamous
Mother cares for young briefly
Less receptors
Same levels of oxytocin and vasopressin

5. Why might these voles use different reproductive strategies?
Prairie voles:
Resource poor habitat
Monogamous
Both parents care for young
Montane voles:
Resource rich habitat
Nonmonogamous
Mother cares for young briefly

6. haploid
X 23
in humans
X 23
in humans
diploid
X 23
in humans
Sexual Reproduction = The combination of genes inherited from Mom and Dad.

7. Asexual
Reproduction
Sexual
Reproduction
vs.
extremely low
genetic diversity
greater genetic
diversity

8. Asexual Reproduction genetically identical to parent
(this tree can reproduce both sexually and asexually)

9. Why does sexual reproduction exist?
Cons:
Need two individuals
Hard to find mate
Diseases/Competition
Pros:
Genetic diversity

10. Screw worm
flies

11. F M
sterile
Sterile male screw worm flies led to decreased populations because of screw worm monogamy.

12. F M
sterile
In most other species, because females mate with multiple males, introduction of sterile males has little effect.
Sterile male screw worm flies led to decreased populations because of screw worm monogamy. F M
sterile

13. Hi, want to study biology together?
In most other species, because females mate with multiple males, introduction of sterile males has little effect.
Hi, want to study biology together? F M F M
fertile
sterile

14. 10-40% of offspring in “monogamous” bird species are fathered by an extra-pair male

15. Social Monogamy = pair lives/works together, but not “faithful”
Sexual Monogamy = pair raise young and only copulate with each other

16. In mammals, child-rearing is most commonly done by the female
In mammals, child-rearing is most commonly done by the female. She provides milk.

17. Less than 0.01% of mammals are monogamous

18. Do Males and Females have different attitudes toward sex and relationships?

19. On a college campus an attractive male or female asked the opposite sex: “I have been noticing you around campus. I find you very attractive…”
Female answers:
…Would you go out with me tonight?
= 50% yes
Male answers:
…Would you go out with me tonight?
= 50% yes

20. On a college campus an attractive male or female asked the opposite sex: “I have been noticing you around campus. I find you very attractive…”
Female answers:
…Would you go out with me tonight?
= 50% yes
…Would you come to my apartment tonight?
= 6% yes
Male answers:
…Would you go out with me tonight?
= 50% yes
…Would you come to my apartment tonight?
= 69% yes

21. On a college campus an attractive male or female asked the opposite sex: “I have been noticing you around campus. I find you very attractive…”
Female answers:
…Would you go out with me tonight?
= 50% yes
…Would you come to my apartment tonight?
= 6% yes
…Would you go to bed with me tonight?
= 0% yes
Male answers:
…Would you go out with me tonight?
= 50% yes
…Would you come to my apartment tonight?
= 69% yes
…Would you go to bed with me tonight?
= 75% yes

22. Why do Males and Females have different attitudes toward sex and relationships?

23. The male perspective on monogamy

24. Eggs require large resource input.
A clutch of bird eggs can be ~20% of bird’s weight.
Sperm are cheap.

25. Human Females:
~1 egg/month
Human Males:
250,000,000 sperm/ ejaculation

26. The female reproductive system

27. Sperm competition: = sperm competition.
Sperm can survive for several days in a woman’s reproductive tract.
In Great Britain in a survey of 4,000 women…
0.5% had sex with 2 different men within 30 minutes…
30% within 24 hours
= sperm competition.

28. The female reproductive system

29. Female mammals provide additional resources in form of milk.

30. Mating pairs share genetic information and possibly help in child-rearing

31. What are the consequences of the different male and female attitudes toward sex and relationships?

32. Zebra Finch

33. Zebra finch pairs were allowed to mate ~9 times

34. Then a new male was brought in and allowed to mate with the female once.

35. Last male advantage
Original male (mated 9 times) fathered 46% of offspring
The last male that only mated once fathered 54% of offspring

36. Last male advantage
To ensure fatherhood males mate guard and produce copious quantities of sperm

37. After successfully mating, male purple martins call and attract younger males

38. The older males then cuckold the younger male’s females
Younger males with nests near older males only father 29% of eggs in their nests.

39. Older males produce 4. 1 offspring with their mate and 3
Older males produce 4.1 offspring with their mate and 3.6 by younger neighbor’s mate.
Younger males with nests near older males only father 29% of eggs in their nests.

40. What advantage is their for females to accept or solicit EPCs?
Older males produce 4.1 offspring with their mate and 3.6 by younger neighbor’s mate.
What advantage is their for females to accept or solicit EPCs?

41. Gunnison’s Prairie Dogs
Sexually monogamous female squirrels have a 92% chance of successfully giving birth.

42. Gunnison’s Prairie Dogs
Sexually monogamous female squirrels have a 92% chance of successfully giving birth.
Non-monogamous females have a 100% chance of giving birth

43. Can females detect compatible genes?

44. How can a female know which male has successful genes?

45. Females may choose traits, like large displays, that are disadvantageous for male survival.

46. How can females determine “good” males?

47. Color:
Bright coloring can be correlated with health…

48. But a male with a mate is judged as being high quality even if he is less colorful

49. How does evolution work for a behaviors such as monogamy?
bye
monogamous
non-monogamous

50. Voles Prairie Monogamous Both parents care for young More receptors
Montane
Nonmonogamous
Mother cares for young briefly
Less receptors
Same levels of oxytocin and vasopressin

51. How does evolution work for a behaviors such as monogamy?
bye
non-monogamous
monogamous

52. How does evolution work for a behaviors such as monogamy?
After several generations…
monogamous
non-monogamous

53. Males must choose between having more offspring (more mates) or helping to raise fewer offspring (sperm do not require many resources)
Females choose males that can provide “good” genes or resources for offspring
(eggs, gestation, and/or lactation require high resource input)

54. better off helping with these kids or should I mate with someone else?
Am I the only one? Am I
better off helping with these
kids or should I mate
with someone else?
Is this the best I can do?
Maybe I can find someone
with better genes or
more genetic diversity.

55. How does sexual reproduction generate genetic diversity?
Asexaul
Reproduction
Sexaul
Reproduction
vs.
extremely low
genetic diversity
greater genetic
diversity
How does sexual reproduction generate genetic diversity?

56. Gene for
growth hormone
Gene for
brown hair pigment
Gene for
hemoglobin
Gene for
DNA polymerase
Gene for
blue eye pigment
Haploid
chromosomes

57. Gene for growth hormone Gene for hair color Gene for hemoglobin
Allele for
low express
(short)
Allele for
black hair
Allele for
sickle cell Hb
Gene for
growth hormone
Gene for
hair color
Gene for
hemoglobin
Diploid
chromosomes
Allele for
high express
(tall)
Allele for
black hair
Allele for
normal Hb

58. Fig 1.5
Each pair of chromosomes is comprised of a paternal and maternal chromosome

59. Fig 1.11
meiosis
Diploid Haploid

60. Meiosis splits apart the pairs of chromosomes.
Fig 3.16
X 23
in humans
Meiosis splits apart the pairs of chromosomes.

61. haploid
X 23
in humans
X 23
in humans
diploid
X 23
in humans
Inheritance = The interaction between genes inherited from Mom and Dad.

62. sister chromatids= replicated DNA (chromosomes)
tetrad= pair of sister chromatids
Fig 3.12

63. Meiosis splits apart the pairs of chromosomes.
Fig 3.16
X 23
in humans
Meiosis splits apart the pairs of chromosomes.

64. How does sexual reproduction generate genetic diversity?
Asexaul
Reproduction
Sexaul
Reproduction
vs.
extremely low
genetic diversity
greater genetic
diversity
How does sexual reproduction generate genetic diversity?

65. Crossing-over (aka Recombination) Fig 3.10 DNA cut and religated

66. Fig 3.10
Crossing-over:
Proteins in the cell cut and religate the DNA, increasing the genetic diversity in gametes.

67. Fig 3.10
Crossing-over:
Proteins in the cell cut and religate the DNA, increasing the genetic diversity in gametes.

68. Fig 3.10
Crossing-over:
Proteins in the cell cut and religate the DNA, increasing the genetic diversity in gametes.

69. How does sexual reproduction generate genetic diversity?
Asexaul
Reproduction
Sexaul
Reproduction
vs.
extremely low
genetic diversity
greater genetic
diversity
How does sexual reproduction generate genetic diversity?

70. Fig 3.17
Independent Assortment
(aka Random Assortment)

71. 2 possibilities for each pair, for 2 pairs
Fig 3.17
Independent Assortment
2 possibilities for each pair, for 2 pairs
22 = 4 combinations

72. 2 possibilities for each pair, for 23 pairs
Fig 3.17
Independent Assortment
2 possibilities for each pair, for 23 pairs
223 =
8,388,608
combinations

73. Crossing-over
Meiosis:
In humans, crossing-over and independent assortment lead to over 1 trillion possible unique gametes.
(1,000,000,000,000)
Meiosis I
(Ind. Assort.)
Meiosis II
4 Haploid cells, each unique

74. Fig 3.12

75. Fig 3.12
4 haploid cells

76. {Producing gametes}
Sexual reproduction creates genetic diversity by combining DNA from 2 individuals, but also by creating genetically unique gametes.
{Producing more cells}

77. haploid
X 23
in humans
X 23
in humans
diploid
X 23
in humans
Inheritance = The interaction between genes inherited from Mom and Dad.

78. Do parents’ genes/traits blend together in offspring?

79. In many instances there is a unique pattern of inheritance.
Fig 2.6
In many instances there is a unique pattern of inheritance.
Traits disappear and reappear in new ratios.

80. from DNA to Protein: from gene to trait
Fig 1.6
from DNA to Protein: from gene to trait

81. from DNA to Protein: from gene to trait
Fig 1.7
from DNA to Protein: from gene to trait
Molecular
Cellular
Organism
Population

82. Genotype
Phenotype

83. Human blood types
Fig 4.11

84. Fig 4.11
One gene with three alleles controls carbohydrates that are found on Red Blood Cell membranes A A B
RBC A B
RBC
RBC B A B A B A A B B A A B B
Allele O = no carbs
Allele A = A carbs
Allele B = B carbs

85. Human blood types
Fig 4.11

86. We each have two versions of each gene…
RBC A A A So A A A A
Genotype could be
A and A OR
A and O

87. Recessive alleles do not show their phenotype when a dominant allele is present.
RBC A A A A A A A
Genotype could be
A and A OR
A and O
See Fig 4.2

88. What about…
RBC
Genotype = ??

89. What about…
RBC
Genotype = OO

90. What about… A B
RBC B A A B B A A B

91. What about… A B
RBC B A A B B A A B
Genotype = AB

92. Human blood types
Fig 4.11
AA or AO
BB or BO AB OO

93. If Frank has B blood type,
his Dad has A blood type,
And his Mom has B blood type…
Should Frank be worried?

94. Mom=B blood
BB or BO
Dad=A blood
AA or AO
possible
genotypes

95. Mom=B blood BB or BO Dad=A blood AA or AO all B / 50% B and 50% O
possible
genotypes
all B / 50% B and
50% O
all A / 50% A and
50% O
Gametes

96. Mom=B blood BB or BO Dad=A blood AA or AO Gametes all B / 50% B and
possible
genotypes
Gametes
all B / 50% B and
50% O
all A / 50% A and
50% O
Frank can be BO
= B blood
…no worries

97. Mom=B blood BB or BO Dad=A blood AA Gametes all B / 50% B and 50% O
Grandparents
AB and AB
Mom=B blood
BB or BO
Dad=A blood AA
possible
genotypes
Gametes
all B / 50% B and
50% O
all A
Frank can be BO or BB
= B blood
…Uh-Oh

98. Pedigree, tracing the genetic past
Dom.
Rec.
Rec.
Dom.

99. Fig 2.11

100. We can also predict the future
Fig 2.6

101. Inheritance of blood types
Mom = AB
Dad = AB

102. Inheritance of blood types
Mom = AB
Dad = AB
Gametes:
A or B
A or B

103. Mom = AB Dad = AB A or B A or B Gametes: Dad A or B 25% AA 50% AB
Inheritance of blood types
Mom = AB
Dad = AB
A or B
A or B
Gametes:
Dad
A or B
Chance of each phenotype for
each offspring
25% AA
50% AB
25% BB AA
A or B AB
Mom AB BB

104. Single genes controlling a single trait are unusual
Single genes controlling a single trait are unusual. Inheritance of most genes/traits is much more complex…
Dom.
Rec.
Rec.
Dom.

105. Genotype
Phenotype
Genes code for proteins (or RNA). These gene products give rise to traits…

106. Human blood types
Fig 4.11
AA or AO
BB or BO AB OO

107. Genotype
Phenotype
Genes code for proteins (or RNA). These gene products give rise to traits…
It is rarely this simple.

108. Fig 4.3
Incomplete dominance

109. Fig 4.4

110. Wednesday: Mapping and Epigenetics